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View Full Version : Maya MentalRay How to resize that light glow size?? Even turn it off.


humhumhum
10-17-2012, 03:39 AM
Hello everybody can I ask a help??
When I using maya with mental ray. I have a red ball with reflection material and a plane and a spotlight in the scene.
I tried serial way to moving spotlight's position and near or far. But spotlight's reflection glow size on the red ball surface has not any change, Always big as picture.

Q1.Have everybody know how to resize the spotlight and directional lignt's reflection point(glow) size??How to make it smaller??

Q2.Can remove light glow as Vray area light "affect reflections" option is off.

Thank for your reading and sorry for my English..

https://bzhnoa.bay.livefilestore.com/y1pLJtBnk5HqUIqQJDvTkuvWAAx9Cay47v-Tpre-cBYD-l1k3KeF0q7UthbNuLveJ3MbAsn-gHEsf_pxJUHot0VqL0UY1GWDRP9/Question.jpg?psid=1

catche
10-18-2012, 07:20 PM
That "glow" is called a specular reflection, and has to with the glossiness and reflection intensity of the shader. Higher glossiness = narrower specular and more clear reflections (more mirror-like), lower glossiness = wider specular and more blurred out reflections

humhumhum
10-20-2012, 03:13 AM
Thank for your advise, it is helpful for me. I recognized the specular reflection size about object size in the world of maya.
So I made another test. This time, I draw a big sphere(6 unit) and small sphere(2 unit, are not clone). Both are smooth and same material(Mia_material-Chrome adjust roughness to 0 and Glossiness to 0) and a spotlight and a plane.
http://114.32.165.173/Picture/material.jpghttp://114.32.165.173/Picture/render.jpg

RenderImage
http://114.32.165.173/Picture/scene.jpg


And I notice the specular reflection point size is different. I agree as you said that glossiness effect the specular reflection. But how about different size have different specular reflection point??
I am very confuse. Becouse this rule is very important.

1.If a light is not effect to the specular reflection point size(I know intensity and decay rate are different have different reflection point. But small ball is small big ball is big point, Same).
2.Adjust material's glossiness value is work. But even max value the size is different.

In real world, I use a small light to light a chrome ball, If the light close the chrome ball, and it will be have a big reflection. If the light far a away, and the reflection will be smaller and smaller unit be a point.
The effect very like area light effect. If I can turn off spotlight or directional light's point, and the reflection light is instead by arealight, I think that's ok.
If not I really what to know how to adjust object's proportion.
I really want reslove the problem.

Thank for you buddy..

FranciscoSCN
10-20-2012, 07:53 PM
Your spotlight emits light from an infinite point, so in order for it to be reflected as a big specular highlight, you have to cheat in the material. Also because of it being an infinite point, the distance of the light does not change the size of the specular highlight, which seems to be your problem. For that, your only solution would be area lights.

bpx
12-05-2012, 01:13 AM
you can turn the specular off in the advanced section of the mia_material_x attributes windows, and as FranciscoSCN stated, you should go with an area light with a quadratic decay and the mental ray light shape option checked (also check the "visible" option) and remember to try to always work in a real world scale. good luck!

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